Extensive bilateral renal metastases of non-small cell lung carcinoma caused acute kidney injury resulting in end-stage renal disease

Non-small cell lung carcinoma unusually causes clinically relevant metastases in the kidney while they are usually found only in autopsy. Acute kidney injury (AKI) due to direct metastatic invasion of a solid tumor is also very rare whereas it usually happens with hematologic malignancy, including lymphoma. We report a case with these two rarities. A 54-year-old man who had a 6.7 × 6.0 cm-sized tumor in the left upper lobe of the lung in computed tomography was diagnosed as squamous cell lung carcinoma with bronchoscopy with biopsy. His renal function was normal and no proteinuria or hematuria was recognized. He underwent left upper lobectomy and the pathologic examination revealed pT4N1M0 stage IIIA disease. Four months after the surgery, a single brain metastasis in the right frontal lobe found in brain magnetic resonance imaging was treated with Gamma Knife radiosurgery. He presented with macroscopic hematuria and AKI (the serum creatinine level was 1.35 mg/dL) nine months after surgery. The cause was enormous bilateral renal metastases, maximally 8 cm-sized lesions with poor enhancement, which were found in enlarged bilateral kidneys in enhanced CT. Intrapulmonary metastatic lesions were also newly detected. Chemotherapy with pembrolizumab, an antibody against anti-programmed cell death protein 1, had little effect and his renal function continued to decline rapidly, resulting in end-stage renal disease and maintenance hemodialysis. Chemotherapy with carboplatin and paclitaxel was additionally performed. However, two months after hemodialysis induction, the patient died with pneumonia and acute respiratory distress syndrome.